Technical Field
The present disclosure relates to a display device, and more particularly, to a display device for generating sound by vibrating a display panel.
Description of the Related Art
With the development of various portable electronic devices, such as a mobile communication terminal and a notebook computer, a requirement for a display device applicable thereto is increasing. The display devices include a liquid crystal display device, an electroluminesce display device, a light emitting diode display device, and an organic light emitting diode display device.
Among these display devices, the liquid crystal display (LCD) device typically includes an array substrate including an array of thin film transistors, an upper substrate including a color filter layer and/or a black matrix, etc., and a liquid crystal material layer formed therebetween, wherein an alignment state of the liquid crystal is controlled according to an electric field applied between two electrodes of a pixel area, and thus, the transmittance of light is adjusted to display images.
In a display panel of such a liquid crystal display device, an active area configured to provide an image to a user and a non-active area, which is a peripheral area of the active area, are defined. The display panel is usually manufactured by attaching a first substrate, which is an array substrate having a thin film transistor formed therein to define a pixel area, and a second substrate, which is an upper substrate having a black matrix and/or color filter layer formed thereon, to each other.
The array substrate or first substrate, on which a thin film transistor is formed, includes a plurality of gate lines GS extending in a first direction and a plurality of data lines DL extending in a second direction perpendicular to the first direction, and one pixel area P is defined by each gate line and each data line. One or more thin film transistors are formed in one pixel area P, and gate and source electrodes of each thin film transistor may be connected to a gate line and a data line, respectively.
Among these display devices, the liquid crystal display device does not have its own light-emitting element and thus needs a separate light source. Therefore, the liquid crystal display device has a back-light unit having a light source, such as an LED, which is arranged at the rear surface thereof and irradiates a light toward a front surface of the liquid crystal panel thereof, thereby implementing a recognizable image.
An organic light emitting diode (OLED) display device has advantages of a fast response time, a high light emitting efficiency, a high luminance, low power consumption, and a wide viewing angle, due to using OLEDs, which are self-emitting elements. In the organic light emitting diode display device, sub-pixels including organic light emitting diodes are arranged in a matrix form, and the brightness of sub-pixels selected by a scan signal is controlled according to a gray scale of data.
Meanwhile, a set apparatus or finished product including such a display device as described above may include, for example, a television (TV), a computer monitor, or an advertising panel. Such a display device or set apparatus may include a sound output device, such as a speaker, for generating and outputting sound relating to output images.
It is typical that a company that manufactures a display device, such as a liquid crystal display device or an organic light emitting diode display device, manufactures only the display panel or display device excluding sound functionality, while another company manufactures a speaker and assembles the speaker with the manufactured display device to complete a set apparatus capable of outputting images and sound.
FIG. 1 is a plan view of a speaker included in a related art display device. As shown in FIG. 1, a related art display device 1 includes a speaker 2 disposed at a rear part or a lower part of the display panel. In this structure, sound generated by the speaker 2 does not progress directly towards a viewer, who is viewing an image from the front side of the display device 1, but instead progresses toward the rear part or the lower part of the display panel rather than a front part of the display panel on which the images are being displayed.
Further, when sound generated from the speaker 2 progresses toward the rear part or the lower part of the display panel, the sound quality may be degraded due to an interference with sound reflected by walls, floors, or other surfaces at the rear or below the display panel.
Also, sound generated by a speaker included in the related art display device is not oriented toward a viewer of the display device and may thus undergo diffraction, which degrades the sound localization. Moreover, in configuring a set apparatus, such as a TV, a speaker may occupy an undesirably large amount of space, which imposes a restriction on the design and spatial arrangement of the set apparatus.
Therefore, there has been an increasing requirement for technology which can improve the quality of sound output from a display device and prevent the viewer's immersion from being disturbed.